[URL="http://api.tweetmeme.com/share?url=http://sports.espn.go.com/nfl/recap?gameId=311016008&service=bit.ly&source=espn"][IMG]http://api.tweetmeme.com/imagebutton.gif?url=http://sports.espn.go.com/nfl/recap?gameId=311016008[/IMG][/URL]Alex Smith's fourth-down, 6-yard pass to Delanie Walker gave San Francisco the go-ahead touchdown with 1:51 left, lifting the 49ers to a 25-19 win over the previously unbeaten Detroit Lions.